The present invention relates to a needle selection device, and relates more specifically to such a needle selection device installed in a circular knitting machine and controlled to selectively lift the needles.
Various devices have been disclosed for selective raising of the needles in circular knitting machines for knitting different pattern works. U.S. Pat. No. 4,604,877, entitled "NEEDLE SELECTION DEVICE FOR KNITTING MACHINES" shows a device including a pair of side-by-side stacks of selector slides or cams supported for individual horizontal sliding movement between innermost active and outermost inactive radial positions. This structure of needle selection device does not allow the user to change the needle selection mode during the knitting of the machine. U.S. Pat. Nos. 4,799,366 and 4,023,383 teach the use of a stationary electromagnetic actuator for acting by magnetic attraction on wire springs incorporated inside selection sinkers inserted inside the slots under the needles and the needle pushers. The disadvantage of this structure of needle selection system is that the wire springs will wear out quickly with use. U.S. Pat. Nos. 3,948,062 and 4,793,159 disclose an electronic means for selective raising of the needles in circular knitting machines by the selective raising of jacks individually related to the needles in the cylinder needle slots. However, this electronic means is acted with a complicated lever action structure.